Heavy rain swamped cars across parts of Nassau and Suffolk Counties Wednesday morning. / New York State Police Twitter

by Doyle Rice, USA TODAY

by Doyle Rice, USA TODAY

Torrential overnight rain brought floods to portions of the Northeast and New England Wednesday, a day after heavy rain swamped the Mid-Atlantic and two days after Detroit saw historic floods.

Wednesday morning, floods stranded drivers in Long Island, where more than a foot of rain fell overnight. Central and eastern Long Island roads that were still open had bumper-to-bumper traffic Wednesday morning.

Islip, N.Y., picked up 13.26 inches of rain overnight, which is more than the city typically gets in an entire summer.

If verified, that amount would break the all-time New York State record for rainiest day in the state's history, the National Weather Service said.

The heavy rain also spread into southern Connecticut, where cars were submerged off I-95 near Branford, the Weather Channel reported.

Flood warnings and watches were posted across most of New England.

On Monday in Detroit, a near-record 4.57 inches fell, the second-rainiest day in the city's history. Two people were killed in the flooding.

Tuesday, it was the Washington/Baltimore area that saw near-record rain and devastating floods, as Tuesday was the second-wettest day in Baltimore's history, with over six inches of rain reported.

That's more than Los Angeles has received the entire year.

The dismal weather is all courtesy of an unusually potent (for summer) low-pressure area that's been tracking along a very slow moving front, according to AccuWeather.

Unseasonably cool air will filter in behind the storm for the end of the week, AccuWeather meteorologist Jordan Root reports.